Permanent magnet containing nickel, aluminum, cobalt, and chromium



Patented Jan. 14, 1936 PitRMANEN'I. MAGNET CONTAINING NICK- EL, ALUMINUM, MIUM COBALT,

AND CHRO- Tokushichi Mishima, Yodobashi-ku, Tokyo. Japan No Drawing.

Original application January 20,. 1932. Serial No. 587,822. plication August 7, 1935, Serial No. 35.207.

Divided and this al Japan August 27, 1931 4 Claims.

This invention relates to a strong permanent magnet and forms a divisional from the ccpending application 587,822 filed January 20, 1932.

This permanent magnet contains the main ele- 5 ments iron, nickel and aluminium, with iron as basic element, nickel 5 to 40% and aluminium '1 to 20%; with the auxiliary elements cobalt 0.5 to 30%, chromium 1 to 5% with or without carbon from trace to 1.5%.

In said original application 587,822 it is described that a so-called "irreversible nickel steel can be changed into a "reversible steel by the addition of aluminium thereby obtaining a strong magnetic alloy. According to the invention it has been found that the addition of a proper amount of other metals as auxiliary elements will further improve the magnetic properties as well as the tenacity and ductility of the permanent magnet .and facilitate the mechanical working of the'magnet.

It is well known that the more minute the microstructure of the magnet steels is, the greater is the increase in the number of molecular magnets arranged irregularly at the boundaries of the crystal grains so that consequently the coercive force and the residual magnetism. also increase. This feature is gained by the addition of certain amounts of one or more auxiliary metals to the main elements iron, nickel and aluminium in the proportions herein given.

According to this invention it has been found that an addition of cobalt and chromium in a proper amount also improves-the magnetic propis: chromium 1 to 5% and cobalt 0.5 to

erties of the steel and that in addition also the In this case also the number of the molecular magnets arranged irregularly at the boundary of the crystal grains is increased, and higher coercive force and stronger residual magnetism are obtained. I 5

Actual examples for this case are given below:

Chemical composition (percent) Magnetic properties Coercive Residual Alumin- Chrolorce (Hc) magnetism Iron Nickel iu'm mium Cobalt (0mm) (Br) (001583) 02.5 10.0 0.0 2 1 10,000 05.3 14.0 2.0 2.5 20.0 200 10,000 58.8 24.0 0.0 2.0 0.0 200 9,800 52.3 00.0 10.0 2.5 5.0 520 0.500 15 In this case it is also noted that the presence of carbon of below 1.5% and/or a small amount of impurities does not materially aliect the magnetic properties of the alloy. 20

I claim:

1. A permanent magnet comprising 5 to 40% nickel, 7 to 20% aluminum, 0.5 to 30% cobalt,-

1 to 5% chromium and the remainder iron.

2. A permanent magnet comprising 5 to 40% 25 nickel, 7 to 20% aluminum, 0.5 to 30% cobalt.

1 to 5% chromium and the remainder substantially iron.

3. A permanent magnet comprising 5 to 40% nickel, 7 to 20% aluminum, 0.5 to 30% cobalt, 30 1 to 5% chromium, from trace to 1.5% carbon and the remainder iron.

4. A permanent magnet comprising 5 to 40% nickel, 7 to 20% aluminum, 0.5 to 30% cobalt,

1 to 5% chromium, from trace to 1.5% carbon 35 and the remainder substantially iron.

TOKUSHICHI IWISHIMA. 

